The invention relates to a trimmer head for a trimmer comprising an elongate trimmer line that is secured by clamping in the base member of the trimmer head and projects through a trimmer line opening in the base member to the exterior and, upon rotation of the trimmer head, defines a cutting plane. The trimmer head further comprises a clamping device arranged in the base member of the trimmer head for clamping the trimmer line. The clamping device comprises a clamping member that is movable about a pivot bolt, wherein the pivot axis of the pivot bolt is positioned in a plane that is approximately parallel to the cutting plane and wherein the clamping member is spring-loaded by a clamping spring into a clamping position. In the clamping position of the clamping member, the trimmer line is secured between a clamping surface and the clamping member. A centrifugal force which is acting at the trimmer line loads the clamping member in the clamping position in its clamping direction. The clamping surface and the support of the pivot bolt are formed on an a common component.
EP 0 824 854 B1 discloses a trimmer head in which the trimmer line is secured by means of a spring-loaded clamping member in the trimmer line opening. The clamping member is pivotable about a pivot axis that is positioned parallel to the axis of rotation; the centrifugal force that is acting on the trimmer line and the clamping member increases the clamping action exerted by the clamping member.
EP 1 586 234 B1 discloses a trimmer head of the aforementioned kind in which the clamping member, the pivot bolt of the clamping member, and an outlet sleeve for the trimmer line are formed together as a common cylindrical component. The pivot bolt is positioned in a plane that is approximately parallel to the cutting plane of the trimmer line, wherein the clamping member is spring-loaded by a clamping spring into its clamping position. In the clamping position of the clamping member, the trimmer line is secured between a clamping surface provided at the housing and the clamping member. The centrifugal force acting on the trimmer line loads the clamping member positioned in the clamping position in the clamping direction, i.e., the clamping action is thereby enhanced. The clamping surface and the support of the pivot axis of the clamping member are formed together in the common cylindrical component which can move in the base member of the trimmer head about an axis that is parallel to the axis of rotation.
The configuration of the clamping device is complex and the rotational support of the clamping device in the base member of the trimmer head is susceptible to failure.